Erlangen 2022 – scientific programme
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A: Fachverband Atomphysik
A 23: Ultra-cold atoms, ions and BEC III (joint session A/Q)
A 23.1: Invited Talk
Thursday, March 17, 2022, 10:30–11:00, A-H2
Chemistry of an impurity in a Bose-Einstein condensate — •Arthur Christianen1,2, Ignacio Cirac1,2, and Richard Schmidt1,2 — 1Max-Planck-Institut für Quantenoptik, Garching, Germany — 2Munich Center for Quantum Science and Techonology, Munich, Germany
In ultracold atomic gases, a unique interplay arises between phenomena known from condensed matter, few-body physics and chemistry. Similar to an electron in a solid, a quantum impurity in an atomic Bose-Einstein condensate is dressed by excitations from the medium, forming a polaron quasiparticle with modified properties. At the same time, the atomic impurity can undergo the chemical reaction of three-body recombination with atoms from the BEC, which can be resonantly enhanced due to universal three-body Efimov bound states crossing the continuum. As an intriguing example of chemistry in a quantum medium, we show that such Efimov resonances are shifted to smaller interaction strenghts due to participation of the polaron cloud in the bound state formation. Simultaneously, the shifted Efimov resonance marks the onset of a polaronic instability towards the decay into larger Efimov clusters and fast recombination.
References: [1] A. Christianen, J.I. Cirac, R. Schmidt, "Chemistry of a light impurity in a Bose-Einstein condensate", arXiv:2108.03174 [2] A. Christianen, J.I. Cirac, R. Schmidt, "From Efimov Physics to the Bose Polaron using Gaussian States", arXiv:2108.03175